After letters are delivered to [Harry] at the [hotel], [Uncle Vernon] drives the family to the seashore, buys a gun, and takes them out in a boat to the [hut-on-the-rock], where they all uncomfortably go to bed.

Chapter 4 - "The Keeper of the Keys" - In which Hagrid arrives at the hut and informs Harry that he is a wizard and has been accepted into Hogwarts. Harry also learns the truth about the deaths of his parents and the origin of the scar on his forehead, much to the chagrin of his uncle.

Discovering that [Harry] knows nothing of [Hogwarts], his parents, or the wizarding world, [Hagrid] yells at the [Dursleys] - and informs [Harry] that he is a wizard, and hands him his [Hogwarts letter].

A disbelieving [Harry] learns the story of his life from [Hagrid], discovering that his parents were [head boy and girl] at [Hogwarts], that [Voldemort] killed them and tried to kill [Harry], and that [Harry] survived and destroyed [Voldemort], making him famous.